Re: indexing improvements - advice wanted

[John Swensen]

On Oct 29, 2008, at 3:05 PM, Jaroslav Hajek wrote:

> > FYI, doing a little extrapolation (my values when running the  
> > script took
> > ~1/3 as long as yours for all computations) and assuming my  
> > speedups would
> > be proportionally faster, I compared to how long the same script  
> > takes in
> > Matlab.  The speedups make it comparable in execution time, whereas  
> > before
> > it was significantly slower.
>
> Great! Unfortunately I can't compare Matlab vs. Octave on the same
> machine (I have access to a machine with Matlab, but the disk quota
> prevents me from compiling Octave there), so I couldn't test myself.
> Could you maybe share the numbers? I'm wondering if there are still
> cases (in dense indexing) where we significantly lag behind. For
> instance, we could use multiple threads for long operations (once we
> settle on what MT tools to adopt for Octave). I'm not sure how much
> multithreaded Matlab is, though.
> >

Octave from HG 20061029
octave:5> testidx
Elapsed time is 0.722301 seconds.
Elapsed time is 29.7557 seconds.
Elapsed time is 25.1726 seconds.
Elapsed time is 0.367569 seconds.
Elapsed time is 27.2487 seconds.
Elapsed time is 28.4005 seconds.
Elapsed time is 3.3338 seconds.


Octave from HG 20061029 with fast index patch
octave:4> testidx
Elapsed time is 0.53322 seconds.
Elapsed time is 0.555357 seconds.
Elapsed time is 0.629247 seconds.
Elapsed time is 0.161504 seconds.
Elapsed time is 0.161961 seconds.
Elapsed time is 0.112308 seconds.
Elapsed time is 0.446973 seconds.


Matlab 7.4 (2007 something)
>> testidx
Elapsed time is 0.596638 seconds.
Elapsed time is 0.583653 seconds.
Elapsed time is 0.772442 seconds.
Elapsed time is 0.486839 seconds.
Elapsed time is 0.144660 seconds.
Elapsed time is 0.180357 seconds.
Elapsed time is 0.642839 seconds.

Matlab 7.6 (2008a)
>> testidx
Elapsed time is 0.619260 seconds.
Elapsed time is 0.594962 seconds.
Elapsed time is 0.771681 seconds.
Elapsed time is 0.492235 seconds.
Elapsed time is 0.145597 seconds.
Elapsed time is 0.181784 seconds.
Elapsed time is 0.659062 seconds.

Even better than I thought it would be!  Once again, this is awesome.   
Thanks.

John Swensen